High Temperature Sodium Bismuth Titanate Capacitors – A New Product Realized

High temperature dielectric ceramics: a review of temperature-stable high-permittivity perovskites

“…Example minor substituents included Sr, Ca, Ba: a further flattening of the dielectric response was achieved, along with increases in electrical resistivity, through the use of dopants (Mn, Cu, Co). In agreement with earlier work by Li et al, [45] the binary solid solution between Na0.5Bi0.5TiO3 and NaNbO3 displayed a flattened dielectric response over a wide temperature range [46]. Optimum compositions gave r > 1000, and tan < 0.02 over the temperature range -30 to + 200ºC: resistivity was > 10 10 m. The wide variety of compositions described in the 2008 Bridger patent application, with full patent granted in 2010, can be grouped into two categories depending on the temperature range of stable dielectric response: (a) compositions with stable properties from < 0ºC to + 200ºC; (b) higher temperature dielectrics with stability from a minimum temperature 200°C±100°C to an upper limit 400°C ±100°C.…”

“…In a similar manner to NBT-based materials reported by Li et al, for the Na0.5Bi0.5TiO3-NaNbO3 system, and by Bridger et al, for complex compositions based on NBT [45,46]. Dittmer et al, observed a r(T) plateau which exhibited two broad humps originating from the shoulder and broad r peak in the base material.…”

“…Optimum compositions gave r > 1000, and tan < 0.02 over the temperature range -30 to + 200ºC: resistivity was > 10 10 m. The wide variety of compositions described in the 2008 Bridger patent application, with full patent granted in 2010, can be grouped into two categories depending on the temperature range of stable dielectric response: (a) compositions with stable properties from < 0ºC to + 200ºC; (b) higher temperature dielectrics with stability from a minimum temperature 200°C±100°C to an upper limit 400°C ±100°C. Certain dopants increased resistivity and improved voltage coefficients to within ±20 % (or in some cases ±10 %) for electric fields up to 10 MV/m [46,47]. Specific examples of the main NBT parent compositions reported by Bridger et al, and their dielectric properties are presented in summary Table 2.…”

“…Bridger et al, patented a series of high temperature dielectric materials based on the relaxor sodium bismuth titanate (NBT) [46]. A a variety of substituents and dopants were used to broaden and adjust the temperature of the r(T) shoulder and main peak.…”

Effect of Eu Doping on the Structural, Electrical, and Dielectric Properties of K0.5Na0.5NbO3 Ceramics for High-Temperature Capacitor Applications

“…Among lead-free systems, Bridger et al 3 reported that 0.9Bi 0.5 Na 0.5 TiO 3 -0.1KTaO 3 exhibited relatively flat permittivity from 80°C to 260°C. Lim et al 4 showed that BiScO 3 -BaTiO 3 -Bi 0.5 K 0.5 TiO 3 displayed good electrical properties over a wide temperature range.…”